Preheat the oven to 180C/350F/gas mark 4
Use a 20cm/8 inch round cake tin.
Grease and flour the cake tin. Sift the flour and salt into a large bowl. Stir in the sugar. Add the butter and rub in with your fingertips until the mixture resembles fine breadcrumbs. Fold in the sour cream and the milk. Stir in the remaining ingredients and mix until well blended.
Pour the cake mixture into the tin. Smooth over the surface with the back of a spoon. Bake for about 50-60 minutes or until the cake is cooked. Remove from the oven, cool in the tin and then turn out and leave on a rack until cold. Store in an airtight container.
